Electronics > Beginners
DIY Variable power supply
exe:
I can't really suggest anything. I could recommend this one: https://www.eevblog.com/forum/beginners/how-does-blackdog_s-psu-work/msg1456590/#msg1456590 . But it can be too complicated.
May be the best approach would be to start reading literature, do own research, build a few less biffy power supplies, learn from them and then build the one you want. Just keep safety considerations in mind. Also heat dissipation, etc. Usually, the problem is not to output 30V 5A, but, say 1V 5V because of drop out on the pass element (unless it's an smps, which is probably better for your case). Understanding where and why heat is dissipated is crucial. As well as thermal performance.
Alternatively, you can just buy an isolation transformer, beefy diode bridge, a big capacitor, and a ready module. May be a soft-start circuit if transformer is too beefy.
castingflame:
Could you use a PC PSU and and so.e front end to it?
Sent from my SM-N960F using Tapatalk
rstofer:
--- Quote from: exe on March 21, 2019, 02:07:11 pm ---I can't really suggest anything. I could recommend this one: https://www.eevblog.com/forum/beginners/how-does-blackdog_s-psu-work/msg1456590/#msg1456590 . But it can be too complicated.
--- End quote ---
That's quite a transformer. Yet this kind of thing comes up all the time. It is very difficult to design a PS that can deliver 30V 5A and also deliver 1V 5A without a tapped transformer and some kind of winding selection.
We need power sources for the op amps and here they are created from separate windings. Nice!
That schematic is dumbed down according to the author. It clearly shows why bench supplies are not cheap!
It's no big deal for a manufacturer to get a transformer with multiple secondaries. It is particularly easy with toroidal transformers. It is somewhat more difficult for the DIYer.
exe:
--- Quote from: rstofer on March 23, 2019, 05:44:26 pm ---
--- Quote from: exe on March 21, 2019, 02:07:11 pm ---I can't really suggest anything. I could recommend this one: https://www.eevblog.com/forum/beginners/how-does-blackdog_s-psu-work/msg1456590/#msg1456590 . But it can be too complicated.
--- End quote ---
That's quite a transformer. Yet this kind of thing comes up all the time. It is very difficult to design a PS that can deliver 30V 5A and also deliver 1V 5A without a tapped transformer and some kind of winding selection.
We need power sources for the op amps and here they are created from separate windings. Nice!
That schematic is dumbed down according to the author. It clearly shows why bench supplies are not cheap!
It's no big deal for a manufacturer to get a transformer with multiple secondaries. It is particularly easy with toroidal transformers. It is somewhat more difficult for the DIYer.
--- End quote ---
Huh, yeah, that circuit was simplified in two ways: no active rectifier (lt4320), and no pre-regulator. With that pre-regulator multiple taps are not needed. The pre-regulator can be found here: https://wahz.blogspot.com/2015/10/lab-power-supply-project-pre-regulator.html . There is also a discussion of it on this forum, but I wasn't able to find the topic.
I built one power supply with two channels using that pre-regulator, seems to work well (with toroid 30VA). My next build is a psu with 120-200VA.
Rick Law:
--- Quote from: chiken on March 20, 2019, 07:30:35 pm ---Hello everyone, :)
Having Power supply with variable voltage and current would be quite hand to me as a student so i wouldnt fry things every so often,
and since my attempt to buy cheap Variable Psu has failed, and trying to fix chinese boards failed even more :horse: I decided that it would be best to build it myself.
... ...
Critics somewhat allowed, just dont go berserker please hehe
--- End quote ---
Bold and underline added to quoted post
From one amateur to another...
I suppose you are aware that even if you made it yourself, chances are, you would need to do quite a bit of debugging with it also, perhaps even more debugging than with a purchased board.
As an inexperience person myself, I know that after soldering something together, the joints may not be correct, the components could have been overheated, component could have been inserted in reverse... etc., etc.
With a DYI, you are more on-your-own with your one of a kind. With a purchased board, there is a higher probability that at least the board should work. There is a hope that someone else may have the same board and can render advice with that specific board. For example, here with the B3603 digital buck PSU, we have a nice lengthy discussion helping each other modify/find problems:
https://www.eevblog.com/forum/reviews/b3603-dcdc-buck-converter-mini-review-and-how-the-set-key-could-be-fatal/
Perhaps get a cheap board (30V 1-2A) for your initial need to start. Separately do few simple linear regulated ones to learn; then do a few boost/buck switcher to learn; then attack a real adult size 5-10A supply that you want for longer term.
I've to say, tearing down a load (dozen or so) of PSU boards and "car phone charger adapters," I learned a hell of a lot - enough to make a couple that I could use as my "main" project PSU's on my work bench . But, I ultimately continued to use the B3603 as my "bench supply" because home made ones just isn't as nicely packaged.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version